the day i learned i had to start insulin for my type 2 diabetes. me... thinking my only option was the vial and syringe dad used. and me... discovering once-daily levemir® flexpen. flexpen® is prefilled. doesn't need refrigeration for up to 42 days. no drawing from a vial. dial the exact dose. inject by pushing a button. flexpen® is insulin delivery... my way. levemir® (insulin detemir [rdna origin] injection) is a long-acting insulin used to control high blood sugar in adults and children with diabetes and is not recommended to treat diabetic ketoacidosis. do not use levemir® if you are allergic to any of its ingredients. the most common side effect is low blood sugar, which may cause symptoms such as sweating, shakiness, confusion, and headache. severe low blood sugar can be serious and life threatening. ask your healthcare provider about alcohol use, operating machinery, or driving. other possible side effects include injection site reactions. tell your healthcare provider about all medicines you take and all of your medical conditions. get medical help right away if you experience serious allergic reactions, such as body rash, trouble with breathing, fast heartbeat, or sweating.